com.faunos.skwish.sys.filters
Class DeleteSetFilterSegment

java.lang.Object
  com.faunos.skwish.Segment
      com.faunos.skwish.sys.filters.FilterSegment
          com.faunos.skwish.sys.filters.AppendProtectedFilterSegment
              com.faunos.skwish.sys.filters.DeleteSetFilterSegment

All Implemented Interfaces:

Range

public class DeleteSetFilterSegment
extends AppendProtectedFilterSegment

A FilerSegment employing a DeleteSet.

Invariants

Let deletedIds be the underlying DeleteSet.
Let inner be the underlying Segment. Then

      inner.getBaseId() ≥ deletedIds.getMinId()
 

Author:

Babak Farhang

Field Summary

Fields inherited from class com.faunos.skwish.sys.filters.FilterSegment

inner

Fields inherited from class com.faunos.skwish.Segment

validator

Constructor Summary

DeleteSetFilterSegment(Segment inner, DeleteSet deletedIds)
Creates a new instance using the given inner instance, and deletedIds.

Method Summary

void	delete(long startId, int count, boolean purge) Deletes count entries starting at the entry with the specified id.
void	getEntry(long id, ByteBuffer out, ByteBuffer workBuffer) Returns the contents of the entry with the specified id.
long	getEntrySize(long id, ByteBuffer workBuffer) Returns the size of the entry with the specified id.
boolean	isReadOnly() Determines whether this instance is read-only (unmodifiable).

Methods inherited from class com.faunos.skwish.sys.filters.AppendProtectedFilterSegment

insertEntry, insertEntry, killNext

Methods inherited from class com.faunos.skwish.sys.filters.FilterSegment

getBaseId, getEntryChannel, getEntryCount, getEntryPart, getNextId

Methods inherited from class com.faunos.skwish.Segment

contains, delete, delete, getEntry, getEntrySize, getEntryStream, hi, isDeleted, isDeleted, killNext, lo, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DeleteSetFilterSegment

public DeleteSetFilterSegment(Segment inner,
                              DeleteSet deletedIds)

Creates a new instance using the given inner instance, and deletedIds.

Method Detail

delete

public void delete(long startId,
                   int count,
                   boolean purge)
            throws IOException

Description copied from class: Segment

Deletes count entries starting at the entry with the specified id. The contents of the deleted entries may optionally be requested to be purged (overwritten) immediately; o.w. the deleted contents will be purged whenever the segment is compacted or merged with another segment.

Note that purging is not part of any transaction semantic; whether or not a purge immediately takes place on its being signaled is implementation-dependent.

Overrides:

delete in class FilterSegment

Parameters:

startId - the ID of the first entry to be deleted. Must be a valid ID in this segment [baseId, baseId + entryCount)

count - the number of entries to be deleted. Specifies a range of IDs to be deleted: [id, id + count). The range of IDs must be valid entries within this segment; o.w. an exception is raised.

purge - if true, the contents of the deleted entries are signaled to be purged (overwritten) immediately; o.w. the contents will be deleted on the next time the segment is compacted.

Throws:

IOException

getEntry

public void getEntry(long id,
                     ByteBuffer out,
                     ByteBuffer workBuffer)
              throws IOException

Description copied from class: Segment

Returns the contents of the entry with the specified id. If the entry is deleted, the method returns without modifying the out buffer.

Overrides:

getEntry in class FilterSegment

out - the buffer into which the contents are written. Its remaining bytes must be large enough; o.w., an exception is raised.

workBuffer - a work buffer used internally to read offsets. The minimum capacity of this work buffer must be 16

Throws:

IOException

getEntrySize

public long getEntrySize(long id,
                         ByteBuffer workBuffer)
                  throws IOException

Description copied from class: Segment

Returns the size of the entry with the specified id. A work buffer with a minimum size of 16 must be passed in.

Overrides:

getEntrySize in class FilterSegment

Returns:

the size of the entry if present; -1, if deleted.

Throws:

IOException

isReadOnly

public boolean isReadOnly()

Description copied from class: Segment

Determines whether this instance is read-only (unmodifiable).

Overrides:

isReadOnly in class FilterSegment

See Also:

Write operations